She does not itch or scratch or chew at herself. There is no undigested food in her droppings. And it is damp around her chin and neck area. But she continually eats and drinks fluid, like she has never eaten before.

Thank you for getting back to me. Weight loss and wet face/chin/neck area are signs that most commonly accompany dental problems. Dental problems are very common in guinea pigs. Left untreated, they can eventually result in death from malnutrition. The best thing to do is have your guinea pig seen by an experienced guinea pig/rabbit vet. This link will take you to a directory of guinea pig/rabbit vets:

The fur loss can be caused by many different things. Parasites and skin infections usually, but not always, cause itching. There are endocrine disorders that also cause fur loss without itching. since your guinea pig will need to see a vet for the weight loss, be sure to have the vet also examine the skin and fur.

As long as your guinea pig is able to eat, this isn't an emergency, but I recommend setting up an appointment for her early next week. If you have more questions about this, just let me know by clicking on REPLY.